A US drone strike targeting Taliban in northwest Pakistan killed 23 people including three civilians on Friday, officials said, after 16 security forces died in an insurgent attack.
It was the first missile strike to hit North Waziristan tribal district since a diplomatic furore erupted between Pakistan and the United States over a drone attack on March 17, which killed 39 people including civilians.
The pilotless aircraft targeted two compounds in Spinwam, 40 kilometres (25 miles) northeast of Miranshah, the main town in North Waziristan.
"The drones launched two successive attacks. In the first strike they fired two missiles and in the second they released three more," a military official in the area said.
Military officials in Peshawar said the death toll had risen from 20 to 23, with two women and one boy among the dead, although that could not be independently verified.
Another official said the rest of the dead were insurgents, but there was no report of any high value target and their nationalities were unknown.
"The missiles hit a house and a nearby guest house in Hasan Khel town in Spinwam area," another official said, adding that the two buildings belong to a tribesman supporter of local Taliban leader Gul Bahadur.
Local security and administration officials in Miranshah gave a higher toll of 25 dead, including three women and four children.
Most drone attacks have been in North Waziristan, the most notorious Afghan Taliban and Al-Qaeda bastion in Pakistan, where the United States wants the Pakistan military to launch a ground offensive as soon as possible.
Pakistan says its troops are too overstretched to mount such an assault.
In the far north of the troubled region bordering war-torn Afghanistan, 16 security officials were killed on Thursday in Taliban attacks on a checkpost being set up on the frontier, a military official said.
He said 200 armed militants had surrounded the post in the Kharkai area of Lower Dir, a district bordering Afghanistan's eastern Nuristan province.
The first ambush saw 14 security personnel killed, he said, and a further two die in a subsequent attack on troops sent to reinforce the position.
In the first attack, "14 people were killed including nine Fro
ntier Corps soldiers and five police officials," the official said, adding that five or six other officials were wounded.
The violence came as US and Pakistani officials wrangle over their counterterrorism efforts on the border and the unpopular US missile campaign.
The strikes inflame anti-US feeling, which is already running high after the January killing of two Pakistani men in a busy Lahore street by a US embassy official later revealed to be working for the CIA.
Cricketer turned politician Imran Khan has announced he will hold a mass protest in Peshawar city on Sunday against the drone campaign.
Last month's US drone attack led Pakistani civilian and military leaders to publicly protest the civilian casualties, although the drone campaign is believed to operate with the tacit consent of the government.
Islamabad offered compensation to the families of the 39 victims and called the US ambassador to the foreign ministry to formally protest the incident.
Missile attacks doubled last year, with more than 100 drone strikes killing over 670 people in 2010, compared with 45 strikes that killed 420 in 2009, according to an AFP tally.
American drones resumed attacks in Pakistan on April 13 for the first time in nearly a month, targeting fighters from the Al-Qaeda-linked Haqqani network in South Waziristan near the Afghan border.
That strike came one day after a Washington meeting between Lieutenant General Ahmad Shuja Pasha, the chief of Pakistan's Inter-Services Intelligence (ISI) agency, and Leon Panetta, director of the CIA, which runs the drone war.
However on Thursday army chief General Ashfaq Kayani said in a statement that drones "not only undermine our national effort against terrorism but also turn public support against our efforts".
Admiral Mike Mullen, Chairman of the US Joint Chiefs of Staff, on a trip to Islamabad this week accused the ISI of having ties with the Afghan Taliban in Pakistan's northwest tribal belt.
The White House also criticised Pakistan's efforts to defeat the Taliban operating on the border in a report this month that was rejected by Islamabad.